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I have a basic question about Redis connection parameters from CacheManager.NET perspective. In case when we have Redis cluster with a master and 2 slaves, and with quorum of sentinel processes, should we provide the IP:PORT combinations pointing to the sentinel processes OR the actual Redis server processes.

As suggested in https://seanmcgary.com/posts/how-to-build-a-fault-tolerant-redis-cluster-with-sentinel, it is advisable to ask the sentinel process about the actual master before making the connection. And probably that goes in line with Jedis which provides JedisSentinelPool to do the initial lookup.

Essentially what we want is that the load balancing on reads (via CacheManager.NET) and the writes should go to the current master node of the cluster.

jatanp
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CacheManager relies on StackExchange.Redis for the Redis implementation. Therefor, whatever this client library supports, CacheManager does, too.

Unfortunately, sentinel support is not implemented, there are issues on github for years regarding that

That being said, I did some testing with a Multi Master/Slave + Sentinel setup. Added all the non-sentinel nodes as endpoints to the Multiplexer configuration and it kinda works because the Redis Client knows how to handle multiple master/slave instances.

In the process of switching to another master, the client might throw exceptions that it cannot write to a readonly slave and such. CacheManager might retry those calls and after a short amount of time, when the leader election is done, the call should go through.

But this is not 100% stable and I would not put that in production, as "official" support is still missing...

Alternative to running with sentinels, you could run Redis in Cluster mode which should just work, or behind a proxy which deals with all that master/slave stuff.

Twemproxy is one alternative.

I still have to add support for Twemproxy to CacheManager, as many features are simply not available, like Lua scripting or get a list of servers or flush commands... This will come in 1.0.2

Hope that helps.

MichaC
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